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प्रश्न
What are the conditions for obtaining a good interference pattern? Give reasons.
What is the essential condition for obtaining sustained interference?
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उत्तर १
The conditions necessary for obtaining a well-defined and steady interference pattern are:
- The two sources of light should be coherent: This is the essential condition for getting a sustained interference pattern. As we have seen, the waves emitted by two coherent sources are always in phase or have a constant phase difference between them at all times. If the phases and phase differences vary with time, the positions of maxima and minima will also change with time, and the interference pattern will not be steady. For this reason, it is preferred that the two secondary sources used in the interference experiment are derived from a single original source.
- The light should be monochromatic: As can be seen from the condition of bright and dark fringes, the position of these fringes as well as the width of the fringes depend on the wavelength of light and the fringes of different colours are not coincident. The resultant pattern contains coloured, overlapping bands.
- The two interfering waves must have the same amplitude: Only if the amplitudes are equal, the intensity of dark fringes (destructive interference) is zero and the contrast between bright and dark fringes will be maximum.
- The two light sources should be narrow: If the slits are broad, the distances from different points along the slit to a given point on the screen are significantly different and therefore, the waves coming through the same slit will interfere among themselves, causing blurring of the interference pattern.
- The interfering light waves should be in the same state of polarization: Otherwise, the points where the waves meet in the opposite phase will not be completely dark and the interference pattern will not be distinct.
- The two waves should be in the same state of polarization: This is necessary only if polarized light is used for the experiment.
उत्तर २
- The two light sources must be coherent, which implies that the light waves they emit must have a constant phase difference or be the same phase.
- The two series must emit light of the same wavelength, but the amplitude between them should differ as little as possible.
संबंधित प्रश्न
State any one difference between interference of light and diffraction of light
How does the angular separation between fringes in single-slit diffraction experiment change when the distance of separation between the slit screens is doubled?
When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of ______________ .
Four light waves are represented by
(i) \[y = a_1 \sin \omega t\]
(ii) \[y = a_2 \sin \left( \omega t + \epsilon \right)\]
(iii) \[y = a_1 \sin 2\omega t\]
(iv) \[y = a_2 \sin 2\left( \omega t + \epsilon \right).\]
Interference fringes may be observed due to superposition of
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)
A long narrow horizontal slit is paced 1 mm above a horizontal plane mirror. The interference between the light coming directly from the slit and that after reflection is seen on a screen 1.0 m away from the slit. If the mirror reflects only 64% of the light energy falling on it, what will be the ratio of the maximum to the minimum intensity in the interference pattern observed on the screen?
The intensity at the central maximum (O) in a Young’s double slit experimental set-up shown in the figure is IO. If the distance OP equals one-third of the fringe width of the pattern, show that the intensity at point P, would equal `(I_0)/4`.
Why are multiple colours observed over a thin film of oil floating on water? Explain with the help of a diagram.
What is meant by coherent sources?
A double-slit arrangement produces interference fringes for sodium light (λ = 589 nm) that are 0.20° apart. What is the angular fringe separation if the entire arrangement is immersed in water (n = 1.33)?
Two coherent sources whose intensity ratio is 25:1 produce interference fringes. Calculate the ratio of amplitudes of light waves coming from them.
What is interference?
What are coherent sources of light?
Obtain the equation for resultant intensity due to interference of light.
The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio `("I"_"max" - "I"_"min")/("I"_"max" + "I"_"min")` will be ______
In Young's double-slit experiment, in an interference pattern, a second minimum is observed exactly in front of one slit. The distance between the two coherent sources is 'd' and the distance between source and screen is 'D'. The wavelength of the light source used is ______
If the monochromatic source in Young's double slit experiment is white light, then ____________.
The light waves from two independent monochromatic light sources are given by, y1 = 2 sin ωt and y2 = 3 cos ωt. Then the correct statement is ____________.
The distance between the first and ninth bright fringes formed in a biprism experiment is ______.
(`lambda` = 6000 A, D = 1.0 m, d = 1.2 mm)
In a biprism experiment, D = 1 m, `lambda` = 6000 Å. When a convex lens is interposed between the biprism ru1d the eyepiece, then the distance between the images of the slits given by the Jens at two positions are 1.5 mm and 6.0 mm. The fringe width will be ______.
The phenomenon of interference is based on ______.
Two sources of light 0.5 mm apart are placed at a distance of 2.4 m and wavelength of light is 5000 Å. The phase difference between the two light waves interfering on the screen at a point at a distance 3 mm from central bright band is ____________.
In interference experiment, intensity at a point is `(1/4)^"th"` of the maximum intensity. The angular position of this point is at (sin30° = cos60° = 0.5, `lambda` = wavelength of light, d = slit width) ____________.
If two waves represented by `"y"_1 = 3 "sin" omega "t"` and `"y"_2 = 5 "sin" (omega "t" + pi/3)` interfere at a point, then the amplitude of the resulting wave will be about ____________.
A ray of light AO in a vacuum is incident on a glass slab at an angle of 60° and refracted at an angle of 30° along OB as shown in the figure. The optical path length of the light ray from A to B is ______.
Describe Young's double-slit interference experiment.
In biprism experiment the maximum intensity is ‘I0’. If the path difference between the two interfering waves is ‘λ/4’ then intensity at the point on the screen is ______.
`[sin 45^circ = cos 45^circ = 1/sqrt 2]`
In biprism experiment, the 3rd dark band is formed opposite to one of the slits. The wavelength of light used is ______.
(D = distance between source and screen, d = distance between the two narrow slits)
